ROS Integration ============ Introduction ---------------- [ROS](http://www.ros.org) is a set of well-engineered software libraries for building robotics applications. It includes a wide variety of packages, from low level drivers to efficient implementations of state of the art algorithms. As we strive to build intelligent agents and transfer them to real-world (on a real robot), we need to take advantage of ROS packages to complete the robot application pipeline. There are three key applications of integrating iGibson with ROS. - Benchmark existing algorithms in a controlled realistic simulation environment. This allows for comparing learning-based methods with classical methods in simulation environments. - Comparing robots in simulation with robots in the real world. In simulation, iGibson can simulate sensors of a robot and publish as messages. In the real world, a real robot publish sensor messages from onboard sensors. Therefore, it is possible to only change the message subscribed and benchmark the performance of downstream applications. This helps locate domain gap and debug algorithms. - Using ROS functions in simulation, such as many motion planning implementations. The possibility of using iGibson with ROS is unlimited. As a starter, we provide an example of integrating iGibson with ROS for navigation. This is a ROS package integrates iGibson Env with ROS navigation stack. It follows the same node topology and topics as `turtlebot_navigation` package. As shown below, so after a policy is trained in iGibson, it requires minimal changes to deploy onto a real turtlebot. ![](images/node_topo.jpg) Environment Setup ---------------- ## Preparation 1. Install ROS: in this package, we use navigation stack from ROS kinetic. Please follow the [instructions](http://wiki.ros.org/kinetic/Installation/Ubuntu). 2. Install iGibson **from source** following [installation guide](installation.md) in **python2.7**. Note that ROS only supports `python2.7` at the moment, so you need to create python2.7 virtual environment to install iGibson instead of python3.x. ```bash git clone https://github.com/StanfordVL/iGibson --recursive cd iGibson conda create -n py2-igibson python=2.7 anaconda # we support python 2.7, 3.5, 3.6, 3.7, 3.8 source activate py2-igibson pip install -e . # This step takes about 4 minutes source deactivate # This step is important because we will NOT use /envs/py2-igibson/bin/python ``` 3. If you use anaconda for setting up python environment, some tweaks of `PATH` and `PYTHONPATH` variable are required to avoid conflict. In particular: 1. For `PATH`: conda related needs to be removed from `PATH` ```bash echo $PATH | grep -oP "[^:;]+" | grep conda ## Remove these paths from $PATH ``` 2. For `PYTHONPATH`: `/usr/lib/python2.7/dist-packages/`, `/opt/ros/kinetic/lib/python2.7/dist-packages`(ROS python libraries), `/envs/py2-igibson/lib/python2.7/site-packages`(iGibson dependencies) and `` need to be in `PYTHONPATH` **in this exact order**. 4. Create `catkin_ws` folder ```bash mkdir -p ~/catkin_ws ``` 5. Soft-link `igibson-ros` folder to your `catkin_ws/src` and run `catkin_make` to index `igibson-ros` package. ```bash cd /igibson ln -s $PWD/examples/ros/igibson-ros/ ~/catkin_ws/src/ cd ~/catkin_ws && catkin_make ``` 5. Install `igibson-ros` dependencies: ```bash cd ~/catkin_ws rosdep install --from-paths src --ignore-src -r -y ``` ## Sanity check ```bash which python # Should give /usr/bin/python, NOT /envs/py2-igibson/bin/python python -c 'import igibson, rospy, rospkg' # Should run without errors ``` Running ---------------- In order to run iGibson+ROS examples, you will need to perform the following steps: 1. Prepare ROS environment ```bash source /opt/ros/kinetic/setup.bash source ~/catkin_ws/devel/setup.bash ``` 2. Repeat Step 3 from Preparation: sanitize `PATH` and `PYTHONPATH` 3. Here are some of the examples that you can run, including gmapping, hector mapping and navigation. ```bash roslaunch igibson-ros turtlebot_rgbd.launch # Bare minimal bringup example roslaunch igibson-ros turtlebot_gmapping.launch # Run gmapping roslaunch igibson-ros turtlebot_hector_mapping.launch # Run hector mapping roslaunch igibson-ros turtlebot_navigation.launch # Run the navigation stack, we have provided the map roslaunch igibson-ros turtlebot_gt_navigation.launch # Run the navigation stack with ground truth localization ``` The following screenshot is captured when running the bare minimal bringup example. ![](images/sensing.png) The following screenshot is captured when running the gmapping example. ![](images/slam.png) Topics ---------------- Here are all the topics that `turtlebot_rgbd.py` publishes and subscribes. Publishes: | Topic name | Type | Usage| |:------------------:|:---------------------------:|:---:| |`/gibson_ros/camera/depth/camera_info`|`sensor_msgs/CameraInfo`|Camera parameters used in iGibson, same for depth and rgb| |`/gibson_ros/camera/rgb/image`|`sensor_msgs/Image`|RGB image captured in iGibson| |`/gibson_ros/camera/rgb/depth`|`sensor_msgs/Image`|Depth image captured in iGibson, in meters, with dtype being float32| |`/gibson_ros/camera/rgb/depth_raw`|`sensor_msgs/Image`|Depth image captured in iGibson, mimic raw depth data captured with OpenNI cameras, with dtype being uint16, see more [here](http://www.ros.org/reps/rep-0118.html)| |`/gibson_ros/lidar/points`|`sensor_msgs/PointCloud2`|1-beam LiDAR scan captured in iGibson, in meters, with dtype being float32| |`/odom`|`nav_msgs/Odometry` |The pose of `base_footprint` in `odom` frame, generated with groudtruth pose in iGibson| |`/ground_truth_odom`|`nav_msgs/Odometry`|The pose of `base_footprint` in `world` frame, generated with groudtruth pose in iGibson| Subscribes: | Topic name | Type | Usage| |:------------------:|:---------------------------:|:---:| |`/mobile_base/commands/velocity`|`geometry_msgs/Twist`|Velocity command for turtlebot, `msg.linear.x` is the forward velocity, `msg.angular.z` is the angular velocity| |`/reset_pose`|`geometry_msgs/PoseStamped`|Direct reset turtlebot's pose (i.e. teleportation)| ### References - [Turtlebot Navigation stack](http://wiki.ros.org/turtlebot_navigation/Tutorials/Setup%20the%20Navigation%20Stack%20for%20TurtleBot) - [`Move_base` package](http://wiki.ros.org/move_base)